Pisces: Cyprinidae] and Clarias Gariepinus [Pisces: Clariidae] in Lake Hayq, Ethiopia

ADDIS ABABA UNIVERSITY SCHOOL OF GRADUATE STUDIES DEPARTMENT OF BIOLOGY Some aspects of the biology of Garra dembecha [Pisces: Cyprinidae] and Clarias gariepinus [Pisces: Clariidae] in Lake Hayq, Ethiopia A thesis submitted to the School of Graduate Studies, Addis Ababa University in partial fulfillment of the requirements for the degree of Master of Science in Biology (Fisheries and Aquatic sciences) Esayas Alemayehu September 2009 1 DECLARATION I, the undersigned, hereby declare that this thesis is my original work and that all sources of material used for the thesis have been duly acknowledged. Name: Esayas Alemayehu Date___________________________ Signature______________________ Advisor: Dr. Abebe Getahun Signature: _________________________ 2 ACKNOWLEDGEMENT I would like to express my sincere gratitude to my advisor, Dr. Abebe Getahun, for his extraordinary patience, guidance, support and encouragement throughout all the phases of the study. I would also like to thank him for coming down to the study area when I faced problems and for the provision of relevant literature. I am also greatly indebted to Dr. Seyoum Mengistou for his constant encouragement, and effort to make the study as smooth as possible. He is also acknowledged for arranging the budget for the study. I would like to thank Mr. Tadesse Fetahi for suggesting the topic, providing financial and material support, valuable literature and unpublished data. He also introduced me to the local fishermen and members of the Abuna Eyesus Moa Monastery, whose help played a great role for the completion of the study. My deep and sincere thanks is due to Aba G/ Senbet and Aba H/ Giorgis, members of the Abuna Eyesus Moa Monastery, who helped me in setting the gears, measuring the fish and most of all their kindness. Fishermen of Lake Hayq are also acknowledged for helping me in setting nets and the long lines. I am grateful to Ato Kinfe Alula, Director of Birhan Guzo Secondary School, for allowing me to be absent from work for a few days every month during the sampling period. He was also helpful in arranging class schedules so that I can attend the courses at the University. The Department of Biology, AAU, is gratefully appreciated for giving me the opportunity to study for my M.Sc. and for providing financial support during my thesis work. My friends at the Department and University, particularly Workiye Worie, Ashagre Gibtan and Abebe Tadesse, are acknowledged for their support during the preparation of this 3 thesis. I also thank the Ethiopian Meteorological Agency for providing me essential data of Hayq region. I would also like to thank Beteal Assefa for her consistent encouragement from the very inception of the project to its completion. I am indebted to her for being a good friend and a good company in our long trips to the study area. Last but definitely not least, I would like to thank my family whose strong confidence in me was a source of inspiration. I am indebted to my mother and father for encouraging me to study for my M.Sc. My brothers and sister are also acknowledged for supporting me in my study. 4 TABLE OF CONTENTS ACKNOWLEDGEMENT....................................................................................................i List of Tables....................................................................................................................... v List of Figures.....................................................................................................................vi ABSTRACT...................................................................................................................... vii 1. INTRODUCTION........................................................................................................... 1 2. LITERATURE REVIEW................................................................................................ 4 3 DESCRIPTION OF THE STUDY AREA....................................................................... 9 4 MATERIALS AND METHODS……………………………………………………….15 4.1 Field sampling and measurement............................................................................ 15 4.2 Estimation of sex-ratio.............................................................................................15 4.3 Length - weight relationship and Condition Factor.................................................16 4.3.1 Length - weight relationship.............................................................................16 4.3.2 Condition factor................................................................................................ 16 4.3 Food and feeding habit............................................................................................ 17 4.3.1 Stomach content analysis..................................................................................17 4.3.2 Gut content analysis..........................................................................................17 4.3.3 Determination of relative importance of food items.........................................17 4.3.4 Estimation of fish-size and food habit relationship.......................................... 18 4.3.5 Estimation of feeding periodicity..................................................................... 18 5. RESULTS...................................................................................................................... 19 5.1 Size composition of the sample............................................................................... 19 5.2 Sex ratio................................................................................................................... 20 5.3 Length - Weight relationship and condition factor.........................23 5.4 Food and feeding habits...........................................................................................29 5.4.1 Relative contribution of food items.................................................................. 33 5 a. Frequency of occurrence……………………………………………………...33 b. Percent composition by number………………………………………...……36 5.4.2 Fish- size and food habit relationship...............................................................39 5.4.3 Feeding periodicity........................................................................................... 40 6. DISCUSSION................................................................................................................44 7. CONCLUSION AND RECOMMENDATION............................................................ 51 8. REFERENCES.............................................................................................................. 54 6 LIST OF TABLES Table1. Morphometry and limnological parameters of Lake Hayq.................................. 11 Table 2. Monthly number of females and males and sex ratio of G. dembecha in Lake Hayq………………………………………………………………………………...21 Table 3. Ratio of male and female G. dembecha by size class…………………………..21 Table 4. Monthly number of females and males and sex ratio of C. gariepinus in............... Lake Hayq..........................................................................................................................22 Table 5. Ratio of male and female C. gariepinus by size class………………………….23 Table 6. Fulton Condition Factor (Mean ±SE) of G. dembecha captured in monthly.......... samples from Lake Hayq................................................................................................... 26 Table 7. Fulton Condition Factor (Mean ±SE) of C. gariepinus captured in monthly samples from Lake Hayq................................................................................................... 28 Table 8. List of items identified from the gut contents of G. dembecha from Lake Hayq………………………………………………………………………………………3 0 Table 9. A List of items identified from the stomach contents of C. gariepinus from Lake Hayq…………………………………………………………………………………32 Table 10. Relative importance of different items present in the gut of G. dembecha....... from Lake Hayq.................................................................................................................34 Table 11 Relative importance of different items present in the stomch of....................... 7 C. gariepinus from Lake Hayq.......................................................................................... 38 LIST OF FIGURES Figure 1. Map showing Lakes Hayq and Ardibo with sampling sites...............................10 Figure 2. Mean monthly rainfall (mm) of Lake Hayq for the period 2006-2008..............13 Figure 3. Mean maximum and mean minimum air temperature (oC) of Lake Hayq area for 2006-2008.................................................................................................................. 13 Figure 4. Length-frequency distribution of G. dembecha from Lake Hayq......................19 Figure 5. Length-frequency distribution of C. gariepinus from Lake Hayq..................... 20 Figure 6. Length-weight relationship of G. dembecha in Lake Hayq............................... 24 Figure 7. Length-weight relationship of C. gariepinus in Lake Hayq...............................25 Figure 8. Monthly variation in mean Fulton Condition Factor of female and male G. dembecha from Lake Hayq................................................................................................27 Figure 9. Monthly variation in mean Fulton Condition Factor of female and male C. gariepinus from Lake Hayq...............................................................................................28

Load more